Cognitive impairment associated with aging is a major public health problem. Given the expected increase in the proportion of African Americans among the older population, the burden of cognitive impairment is likely to increase disproportionately in this subgroup. Cognitive impairment associated with aging is fundamentally a process of change in an individual's ability over time, yet most studies of cognitive impairment in African Americans have been cross-sectional. Because of the difficulty in accounting for cultural and educational biases associated with test measurement at a single point in time, these studies need to be complemented by examination of change in cognitive function. The goal of the proposed project is to conduct an epidemiologic longitudinal study to identify risk factors for change in cognitive function in older African Americans. Because cognition is composed of dissociable systems that mediate specific types of information processing, we will assess change not only in a global measure of cognition, but in different cognitive systems as well. It is hypothesized that 1) the possession of one or more apolipoprotein e4 alleles will predict decline in global cognitive function, and specifically in episodic memory; 2) more years of education and higher frequency of participation in cognitive activity across the life span will predict less decline in global cognitive function and specifically in episodic memory, working memory, and perceptual speed; and 3) higher levels of depressive symptoms will predict more rapid decline in global cognitive function and specifically in episodic memory and visuospatial ability. To test these hypotheses we will enroll 300 older community dwelling African Americans without dementia at baseline, and with a wide range of educational and lifetime environmental experiences who agree to annual follow-up evaluations and detailed cognitive testing. The faster growth of the aging minority population adds urgency to the need for a better understanding of risk factors related to cognitive decline.